Materials Science and Manufacturing Engineering Miscellaneous Easy Questions and Answers | Page - 140

Materials Science and Manufacturing Engineering Miscellaneous

A cutting tool has a nose radius of 1.8 mm the feed rate for a theoretical surface roughness of Rt = 5 microns is

1. 0.268 mm/rev
1. 0.187 mm/rev
1. 0.036 mm/rev
1. 0.0187 mm/rev

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Nose Radius = 1 – 8 mm, f =? R_t = 5 microns (Peak to valley height.)
0.005 = f²
8R_t

f = √0.005 × 8 × 1.8 = 0.268 mm / rev

Correct Option: A

Nose Radius = 1 – 8 mm, f =? R_t = 5 microns (Peak to valley height.)
0.005 = f²
8R_t

f = √0.005 × 8 × 1.8 = 0.268 mm / rev

In a typical metal cutting operation, using a cutting tool a positive rake α = 10°, it is as observed that the shear angle was 20°. The friction angle is

1. 45°
1. 30°
1. 60°
1. 40°

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α = 10°, φ = 20°
Ernest & Merchants' theory 2φ + β – α = 90°
2 × 20 + β – 10 = 90°
40 + β – 10 = 90°
β = 60°

Correct Option: C

α = 10°, φ = 20°
Ernest & Merchants' theory 2φ + β – α = 90°
2 × 20 + β – 10 = 90°
40 + β – 10 = 90°
β = 60°

In comparison to HSS, super HS contains higher percentage of

1. Tungsten
1. Carbon
1. Vanadium
1. Cobalt

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Vanadium increases the wear resistance of High speed steel.

Correct Option: C

Vanadium increases the wear resistance of High speed steel.

Most of the metal cutting heat goes into the

1. Moving chip
1. Cutting tool
1. Work material
1. Machine tool

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Chip takes away heat from the working zone otherwise tool life and work piece surface finish would get spoiled.

Correct Option: A

Chip takes away heat from the working zone otherwise tool life and work piece surface finish would get spoiled.

Crater wear always starts at some distance from the tool tip because at that point

1. cutting fluid does not penetrate
1. chip tool interface temperature is maximum
1. normal stress on rake face is maximum
1. tool strength is minimum

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Maximum temperature at the chip tool interface is 2 – 3 mm away from cutting edge because shank provides rapid heat dissipation just below the cutting edge.

Correct Option: B

Maximum temperature at the chip tool interface is 2 – 3 mm away from cutting edge because shank provides rapid heat dissipation just below the cutting edge.